Recent explosive growth of data transmission speed results from rapid advancements of network-based transmission technology. According to existing Augmented Category 6 standard (such as TIA-568-C.2 and ISO-11801 ed.2) of an 10 GBASE-T protocol of IEEE 802.3, with an RJ-45 connectors serving as standard interfaces for network connectors, the data transmission speed is 1000 times (10 Gbs/sec) higher than the initial speed (10 Mbs/sec), whereas the operating frequency increases from 16 MHz to 500 MHz. Given the ever-increasing transmission speeds and operating frequencies of broadband networks, it is important to reduce crosstalk. In this regard, crosstalk falls into two categories, namely internal crosstalk and alien crosstalk. The internal crosstalk occurs whenever unwanted capacitive coupling or inductive coupling happens between internal wirings of a single network channel. The alien crosstalk occurs whenever unwanted capacitive coupling or inductive coupling happens as a result of mutual interference of multiple network channels. In general, the routing of the internal circuitry of a single network channel and compensation mechanism can solve the aforesaid problems with internal crosstalk, whereas the aforesaid problems with alien crosstalk can be solved by widening the distance between multiple network channels.
Referring to FIG. 1, there is shown a perspective view of a plurality of first conventional patch panels which stack one above the other. In typical horizontal cablings, horizontal cables are terminated into multiple patch panels that make future “move”, “add” and “change” possible. The patch panels are proximately mounted on equipment racks. The prevailing 24-port patch panel usually features shoulder by shoulder mechanism with port-to-port spacing no more than 18.50 mm due to EIA-310 standard limitation. Standard specifies 450 mm as usable dimension, so a standard compliant patch panel must have 18.50 mm×24 as maximum. Referring to FIG. 2, there is shown a graph of measurement of alien crosstalk of the first conventional patch panel shown in FIG. 1. According to inventor's experiments, even with the maximum spacing 18.50 mm, the severity of alien crosstalk degrades the SNR to an intolerable level.
There have always been new designs that intended to reduce alien crosstalk that is induced to the disturbed network ports. Referring to FIG. 3, there is shown a perspective view of a plurality of second conventional patch panels which stack one above the other. The most-common-seen design typically features port-to-port staggered design. The practical way to do this is enlarge the spacing between the disturbing and the disturbed network ports in a one-axis movement. Referring to FIG. 3, the spacing between the centers of corner network ports and disturbed network port is each denoted with a1 & b1. The spacing between the centers of upper & lower network ports and disturbed network port is each denoted with a2 & b2. The spacing between the centers of side network ports and disturbed network port is each denoted with a3 & b3. The greatest alien crosstalk occurs between the network ports spaced apart by distances a1 & b1. Moderate alien crosstalk occurs between the network ports spaced apart by distances a2 & b2. The least and thus negligible alien crosstalk occurs between the network ports spaced apart by distances a3 & b3 since a3 & b3 has been twice the distance as it is supposed to be.
Referring to FIG. 4, there is shown a graph of measurement of alien crosstalk of the second conventional patch panels shown in FIG. 3. Although alien crosstalk may be considerably reduced therewith, still only a marginal fail can be achieved which is near around 60 dB SNR. But it is still way too insufficient to meet 70 dB SNR that runs 10 Gbps as standard proposed.